The present invention relates to an electrophotographic printer, such as a laser beam printer, and an electrophotographic device, such as an electrophotographic copying machine, and, in particular, it relates to an electrophotographic device having a rotation control means for a photosensitive body.
JP-A-8-248844 (1996), for example, discloses an electrophotographic device in which, after turning off a changer, a photosensitive body is rotated for a predetermined time based on the driving time of the charger until the turning off, to thereby eliminate deterioration of the photosensitive body due to ozone. Although JP-A-8-248844 (1996) discloses reducing deterioration of the photosensitive body due to ozone by rotating the same for a predetermined time, however, no consideration is given to the possible influence this extended rotation has on the shortening of the life time of the photosensitive body.
Other than deterioration due the affects of the to printing beams and due to ozone, the life time of the photosensitive body is affected by the rotation thereof, in particular, with regard to an electrophotographic device using a belt-shaped photosensitive body, in that, if the photosensitive body is rotated additionally, deterioration of the photosensitive body itself is caused. In particular, with regard to a recent electrophotographic device with a higher printing speed, the deterioration of the photosensitive body appears remarkably when such a measure is employed.
An object of the present invention is to provide a method of avoiding deterioration due to rotation of a photosensitive body, as well as of preventing deterioration of the photosensitive body and an electrophotographic device main body due to ozone.
In order to achieve the above object, one of features of the electrophotographic device of the present invention is to reduce the rotating speed of the photosensitive body, when rotating the photosensitive body for the purpose of preventing deterioration thereof due to ozone.
Further, another feature of the present invention resides in an electrophotographic device which comprises a photosensitive body; a charger which uniformly charges the surface of the photosensitive body; and a motor control unit which performs drive control for a motor which operates to rotate and stop the photosensitive body, wherein the feature of the invention is characterized in that the motor control unit includes a plurality of speed levels, including a first speed level for rotating the photosensitive body during printing and a second speed level for rotating the photosensitive body, which second speed level is lower than the first speed level used during the printing, and there is provided a speed change-over means, which changes over the control of the motor speed between the plurality of speed levels, depending on the operating condition of the electrophotographic device.